


let the sky thunder

by Anonymous



Category: Supernatural
Genre: Enthusiastic Consent, Extremely Underage, M/M, Sibling Incest, Watersports
Language: English
Status: Completed
Published: 2019-07-24
Updated: 2019-07-24
Packaged: 2020-07-17 23:54:15
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,459
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19965307
Author URL: https://archiveofourown.org/
Summary: After spending twenty minutes in the same space as Sam while he was holding, Dean would be tense all over and jittery like he was the one with a bursting bladder.And somewhere along the way, Sam noticed. He’d grin at Dean when he took a huge gulp of Kool-Aid or soda. He stopped trying to hide the way his breathing went shallow and uneven when he was close to losing it. Finally, he took to leaving the bathroom door open when their dad was gone.





	let the sky thunder

**Author's Note:**

> I wrote this years ago and never posted it so.... here we are. Mind the tags, Sam is 9 and this is literally just piss play.

It was never really a secret. When Sam was a kid, he’d make Dean pretend the stuffed animals had to go potty and giggle when his brother gave in and made the hissing pee noise. Hell, Sam was still a kid, but one who was fast growing out of his baby fat. Sometimes, when they stood side by side at urinals in truck stops and gas stations, he’d notice his brother watching him out of the corner of his eye. That was normal, he figured. Dean was his big brother – Sam was curious about him, just trying to figure out what was normal and how they compared.

Yeah, normal went out the window real fast.

Dean wasn’t sure when it started, but once he’d noticed, it was impossible to unsee. Sam liked to hold it. In the car, he’d down the last of the bottled water, and say no to offered rest stops, miles and miles of highway between them and the next break. At school, Dean would stop in the bathrooms at lunch, and then again before the walk home, but Sam never did, just waited outside, clutching his books and jostling his leg. In hotels, with the tiny bathroom just a few feet away, Sam would sit on their shared bed, watching TV, squirming ever so slightly, for hours.

It drove Dean crazy. After spending twenty minutes in the same space as Sam while he was holding, Dean would be tense all over and jittery like he was the one with a bursting bladder.

And somewhere along the way, Sam noticed. He’d grin at Dean when he took a huge gulp of Kool-Aid or soda. He stopped trying to hide the way his breathing went shallow and uneven when he was close to losing it. Finally, he took to leaving the bathroom door open when their dad was gone.

Dean had known, for a while, that Sam preferred to relieve himself in the shower cubicle than the toilet. He was used to hearing the distinct hiss and splatter of pee on porcelain, but it was something totally different seeing it. Because Sam wasn’t just peeing in the shower. Oh, no. He was stripping naked, leaning back, bracing himself against the wall, taking his little boy’s cock in his hand, pointing it up his chest, and pissing all over himself.

The first time Dean saw it, he was thirteen, Sam was just nine, and it wasn’t until it was over, Sam sighing and rubbing his hands over himself, petting his stiff little prick, that Dean realized his mouth was hanging open and he was as hard as he’d ever been in his jeans.

After that, it was like Sam was deliberately torturing him with it, squirming and panting while they sat together watching TV, building it up until Dean could barely breath with it, and then running into the bathroom, stumbling out of his clothes, barely making into the tub before letting go.

Eventually, it turned out that Dean had a breaking point, the summer he was fourteen and Sam was ten. One afternoon when they’d spent all day in the car, Sam was practically crawling out of his skin by the time they pulled into the motel. He’d been rubbing his crotch and making tiny, almost inaudible whimpering noises for the last thirty miles, and Dean, stuck in the back seat with him, had been hard for twenty of them.

John dropped the bags in their rooms and headed out for the bar and Sam dashed for the bathroom as soon as the door was closed behind him. Dean followed him, because he really needed to pee too after that car ride. What he saw made his pulse thud in his ears. Sam hadn’t even made it out of his shirt, just shucked his jeans, and his undies were crumpled and soaked in the bottom of the tub. He was groaning, noise echoing in the tiled space along with the harsh patter of urine hitting the ceramic. The bottom half of his white teeshirt was clinging to his skin, wet and transparent. His piss was almost clear and the smell mild, he’d been drinking so much.

Sam’s eyes flickered open, and he met Dean’s gaze. They were barely two arms-lengths apart in the cramped bathroom, and Sam’s eyes were dazed, mouth bitten and red, he looked fucked-out just from holding it, and he was still pissing, splashing all over his legs and the floor of the tub. A cramp of pain through his abdomen reminded Dean that his bladder was full too, and he yanked open his jeans, pushing them down to his knees and standing over the toilet. He was still hard though and nothing came out.

Sam’s eyes flickered down to his erection, and he moaned like a pornstar, fisting his own cock and making a spray of pee go wide, splattering across the bathmat and the tile floor. Dean’s dick jumped. “Dean,” Sam panted. “Let me see, Dean, please,”

Dean groaned and cupped his balls. At this rate he was going to come before he could pee. “Keep talking,” he gritted out.

“Dean. I love your cock, love watching you pee. I wish I could lick your slit after you finish, suck you clean.” The patter of his piss was trailing off into a dribble.

“Fuck, Sam,” Dean mumbled. He could feel his orgasm building in his gut, bladder heavy as his muscles clenched against them.

Sam was cupping his little cock, hard now that he’d finished pissing, hairless and stiff. “Want you to come for me, Dean, want to see it, god, wish you’d do it all over me.”

Making a growling noise that was barely human, Dean staggered two steps to the rim of the tub and aimed his cock at Sam’s middle. Sam gasped and yanked his tee shirt up just as Dean started to come, and Dean groaned helplessly as he shot stripe after stripe of come across his baby brother’s belly. Sam whined high and wanton, swiping a palm full off his stomach and slicking his cock with it, pumping his fist on his shaft with a wet sound because of Dean’s fucking come easing the way.

Dean grunted. “Sam. I’m gonna, I’ve gotta.”

“Yes, Dean, fuck yes, please, Dean!”

“Sure, Sammy?” He was so close, he couldn’t hold it, he was about to lose it and pee everywhere.

“Do it, do it, do it!”

“Fuck,” Dean breathed. At first it felt like he was still hard and nothing would come, and then a few drops dribbled out and a dam broke. Piss sprayed out of his dick in a fan, it had so much force, arching up between them and spattering across Sam’s chest, soaking his teeshirt where it was bunched up under his arms. Sam was groaning and whimpering, one hand working his cock, the other rubbing his stiff nipples, gleaming and dripping with – _fuck_ —Dean’s piss. His head was thrown back against the shower wall and he was shaking, bucking his hips up into his hand.

Dean felt drugged from his orgasm, dizzy with adrenaline and relief, wild with some sort of primal caveman triumph, marking Sam like an animal. He wanted to piss all over him, soak his hair and his face, get hard again and rut against him until they both came all over each other, cover him in Dean’s scent.

“Dean, Dean,” Sam whimpered. “On my cock, do it on my cock, I need to come, Dean!”

“Shit, Sammy,” Dean gasped, bracing a hand against the wall and aiming his stream lower. Pee gleamed and spattered in Sam’s belly button and ran in rivulets down the sharp hollows of his hip bones as Dean trailed it down his stomach to where his hand was working furiously at his red, swollen prick. Clenching all his stomach muscles, Dean sent the last, hard spray of piss over his brother’s hairless, clenched balls and his shining pink cock-head, leaning forward and aiming right at his gaping slit.

Sam howled like a banshee and shook so hard he almost slipped in the wet tub, prick jerking and spitting out strands of watery white come that landed mostly on Dean’s cock, dripping the last of his pee and well on the way to being hard again. Dean groaned, rubbing Sam’s thin little boy come into his skin.

They washed up in silence. Sam changed into clean clothes while Dean made dinner, and washed his shirt and underwear in the sink. Nothing was said as they sat down at the scarred Formica table with plates of canned beans and instant rice, but Dean put a tall glass of water down in front of each of them, and Sam grinned.

**Author's Note:**

> Comments are love!


End file.
